Let (R, m, k) be a complete local Cohen - Macaulay (CM) ring of dimension one. It is known that R has finite CM type if and only if R is reduced and has bounded CM type. Here we study the one-dimensional rings of bounded but infinite CM type. We will classify these rings up to analytic isomorphism ( under the additional hypothesis that the ring contains an infinite field). In the first section we deal with the complete case, and in the second we show that bounded CM type ascends to and descends from the completion. In the third section we study ascent and descent in higher dimensions and prove a Brauer - Thrall theorem for excellent rings.
机构:
Nara Univ Educ, Takabatake, Nara 6308528, JapanUniv Nebraska, Dept Math, Lincoln, NE 68588 USA
Araya, Tokuji
Iima, Kei-ichiro
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Nara Natl Coll Technol, Dept Liberal Studies, Yamato Koriyama, Nara 6391080, JapanUniv Nebraska, Dept Math, Lincoln, NE 68588 USA
Iima, Kei-ichiro
Takahashi, Ryo
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Univ Nebraska, Dept Math, Lincoln, NE 68588 USA
Shinshu Univ, Fac Sci, Dept Math Sci, Matsumoto, Nagano 3908621, JapanUniv Nebraska, Dept Math, Lincoln, NE 68588 USA
机构:
Nagoya Univ, Grad Sch Math, Chikusa Ku, Furocho, Nagoya, Aichi 4648602, JapanNagoya Univ, Grad Sch Math, Chikusa Ku, Furocho, Nagoya, Aichi 4648602, Japan